Determination of in vitro synergy and antibiofilm activities of antimicrobials and essential oil components

Using existing adrentimicrobials with essential oil components to prevent antimicrobial resistance is an alternative strategy. This study aimed to evaluate the resistance status, synergistic combinations, and in vitro biofilm formation activities of clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA), Stenotrophomonas maltophilia and Candida albicans against antimicrobial agents and cinnamaldehyde, carvacrol, eugenol, limonene and eucalyptol. Antimicrobial activities were evaluated by microdilution, cytotoxicity by XTT, synergy by checkerboard and time-kill, and biofilm inhibition by microplate methods. Cinnamaldehyde and carvacrol showed strong antimicrobial activity. Synergistic effects were observed when using all essential oils with antimicrobials. Only two C. albicans isolates showed antagonism with cinnamaldehyde and fluconazole. The constituents showed cytotoxic effects in the L929 cell line (except limonene). A time-kill analysis revealed a bacteriostatic effect on S. maltophilia and MRSA isolates and a fungicidal effect on C. albicans isolates. These results are important for further research to improve antimicrobial efficacy or to develop new agents.

Cinnamaldehyde-Contained Polymers and Their Biomedical Applications

Cinnamaldehyde, a natural product that can be extracted from a variety of plants of the genus Cinnamomum, exhibits excellent biological activities including antibacterial, antifungal, anti-inflammatory, and anticancer properties. To overcome the disadvantages (e.g., poor water solubility and sensitivity to light) or enhance the advantages (e.g., high reactivity and promoting cellular reactive oxygen species production) of cinnamaldehyde, cinnamaldehyde can be loaded into or conjugated with polymers for sustained or controlled release, thereby prolonging the effective action time of its biological activities. Moreover, when cinnamaldehyde is conjugated with a polymer, it can also introduce environmental responsiveness to the polymer through the form of stimuli-sensitive linkages between its aldehyde group and various functional groups of polymers. The environmental responsiveness provides the great potential of cinnamaldehyde-conjugated polymers for applications in the biomedical field. In this review, the strategies for preparing cinnamaldehyde-contained polymers are summarized and their biomedical applications are also reviewed.

Development of pH-Sensitive Magnetoliposomes Containing Shape Anisotropic Nanoparticles for Potential Application in Combined Cancer Therapy

Late diagnosis and systemic toxicity associated with conventional treatments make oncological therapy significantly difficult. In this context, nanomedicine emerges as a new approach in the prevention, diagnosis and treatment of cancer. In this work, pH-sensitive solid magnetoliposomes (SMLs) were developed for controlled release of the chemotherapeutic drug doxorubicin (DOX). Shape anisotropic magnetic nanoparticles of magnesium ferrite with partial substitution by calcium (Mg_0.75Ca_0.25Fe₂O₄) were synthesized, with and without calcination, and their structural, morphological and magnetic properties were investigated. Their superparamagnetic properties were evaluated and heating capabilities proven, either by exposure to an alternating magnetic field (AMF) (magnetic hyperthermia) or by irradiation with near-infrared (NIR) light (photothermia). The Mg_0.75Ca_0.25Fe₂O₄ calcined nanoparticles were selected to integrate the SMLs, surrounded by a lipid bilayer of DOPE:Ch:CHEMS (45:45:10). DOX was encapsulated in the nanosystems with an efficiency above 98%. DOX release assays showed a much more efficient release of the drug at pH = 5 compared to the release kinetics at physiological pH. By subjecting tumor cells to DOX-loaded SMLs, cell viability was significantly reduced, confirming that they can release the encapsulated drug. These results point to the development of efficient pH-sensitive nanocarriers, suitable for a synergistic action in cancer therapy with magnetic targeting, stimulus-controlled drug delivery and dual hyperthermia (magnetic and plasmonic) therapy.

Recent Progress in Proteins-Based Micelles as Drug Delivery Carriers

Proteins-derived polymeric micelles have gained attention and revolutionized the biomedical field. Proteins are considered a favorable choice for developing micelles because of their biocompatibility, harmlessness, greater blood circulation and solubilization of poorly soluble drugs. They exhibit great potential in drug delivery systems as capable of controlled loading, distribution and function of loaded agents to the targeted sites within the body. Protein micelles successfully cross biological barriers and can be incorporated into various formulation designs employed in biomedical applications. This review emphasizes the recent advances of protein-based polymeric micelles for drug delivery to targeted sites of various diseases. Most studied protein-based micelles such as soy, gelatin, casein and collagen are discussed in detail, and their applications are highlighted. Finally, the future perspectives and forthcoming challenges for protein-based polymeric micelles have been reviewed with anticipated further advances.

Development of stimuli responsive polymeric nanomedicines modulating tumor microenvironment for improved cancer therapy

The complexity of the tumor microenvironment (TME) severely hinders the therapeutic effects of various cancer treatment modalities. The TME differs from normal tissues owing to the presence of hypoxia, low pH, and immune-suppressive characteristics. Modulation of the TME to reverse tumor growth equilibrium is considered an effective way to treat tumors. Recently, polymeric nanomedicines have been widely used in cancer therapy, because their synthesis can be controlled and they are highly modifiable, and have demonstrated great potential to remodel the TME. In this review, we outline the application of various stimuli responsive polymeric nanomedicines to modulate the TME, aiming to provide insights for the design of the next generation of polymeric nanomedicines and promote the development of polymeric nanomedicines for cancer therapy.

"Smart" drug delivery: A window to future of translational medicine

Chemotherapy is the mainstay of cancer treatment today. Chemotherapeutic drugs are non-selective and can harm both cancer and healthy cells, causing a variety of adverse effects such as lack of specificity, cytotoxicity, short half-life, poor solubility, multidrug resistance, and acquiring cancer stem-like characteristics. There is a paradigm shift in drug delivery systems (DDS) with the advent of smarter ways of targeted cancer treatment. Smart Drug Delivery Systems (SDDSs) are stimuli responsive and can be modified in chemical structure in response to light, pH, redox, magnetic fields, and enzyme degradation can be future of translational medicine. Therefore, SDDSs have the potential to be used as a viable cancer treatment alternative to traditional chemotherapy. This review focuses mostly on stimuli responsive drug delivery, inorganic nanocarriers (Carbon nanotubes, gold nanoparticles, Meso-porous silica nanoparticles, quantum dots etc.), organic nanocarriers (Dendrimers, liposomes, micelles), antibody-drug conjugates (ADC) and small molecule drug conjugates (SMDC) based SDDSs for targeted cancer therapy and strategies of targeted drug delivery systems in cancer cells.

Polymer-Based Hybrid Nanoarchitectures for Cancer Therapy Applications

Globally, cancer is affecting societies and is becoming an important cause of death. Chemotherapy can be highly effective, but it is associated with certain problems, such as undesired targeting and multidrug resistance. The other advanced therapies, such as gene therapy and peptide therapy, do not prove to be effective without a proper delivery medium. Polymer-based hybrid nanoarchitectures have enormous potential in drug delivery. The polymers used in these nanohybrids (NHs) provide them with their distinct properties and also enable the controlled release of the drugs. This review features the recent use of polymers in the preparation of different nanohybrids for cancer therapy published since 2015 in some reputed journals. The polymeric nanohybrids provide an advantage in drug delivery with the controlled and targeted delivery of a payload and the irradiation of cancer by chemotherapeutical and photodynamic therapy.